Improvement in atmospheric brakes tor railway cars



S Atmospheric Brake for Railway Cars.

Patented April 12, 1870.

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SYLVESTER MARSH, OF LITTLETON, NEW HAMPSHIRE.

Letters Patent No. 101,895, dated April 12, 1870.

IMPROVEMENT IN ATMOSPHERIC BRAKES FOR RAILWAY CARS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it known that I, SrLvEsTnn Manstt, of Littleton, county of Grafton and State of New Hampshire, have invented certain new and. useful Improvements in Atmospheric Brakes for Railroad Cars and other purposes, of which the following is a'spccitication.

This invention relates to the apparatus for descending gradients, for which Letters. Patent No. 44,965 were issued to me on the 8th of November, 1864.

The invention described in said Letters Patent consists in coupling one or more wheels of railway carriages, or other vehicles, to the piston of an air-tight cylinder, filled with air or other fluid, combined with a system of valves and tubes for opening and closing communication between the ends of the cylinder. \Vheu the valves-are open the piston is free to play back and forth, thus allowing the rotation of the wheel with which it is coupled. \Vheu the valves are closed the piston is checked and cannot move, thus arresting the movementof the wheel.

In the practical.operation of this apparatus I have found that although in the upward travel of the car the valves or faucets are left open, yet it takes some power to more the piston and small gears used in the apparatus. For these, under my former arrangement, must more with the wheels, as it would be dangerous to uncouplc them, because they are needed for instant use in case any accident should happen during the ascent.

My object in the present invention is to so combine the coupling devices with the piston or pistons, that the latter shall remain at restduring the ascent of the car, and yet be ready for instantaneous operation should any accident occur \vhigh might otherwise cause the car to descend.

To this end I combine with the car-axle and wheels, and the piston or pistons and their couplings, a ratchet and pawl, clutch, or equivalent device, operating to permit the free rotation of the wheels during the ascent without connnunicating motion to the piston, and in case of the reverse movement or descent of the car, to at once throw'thc pistons in communication with the wheels, for the purpose of retarding or of completely arresting their movement, as may be desired.

To enable others skilled in the art to understand and use my invention, I will now proceed to describe the manner in which the same is or may be carried into efl'ect by-reference to the accompanying drawin Figure 1 is a perspective view of a car-truck with my improvement applied.

Figure 2 is a separate view of the ratchet and pawl for coupling the pistons and car-wheels or axle.

The air-tight cylinders A are arranged on the car as described in Letters Patent hereinbefore referred to. A pipe, a, on each cylinder puts the two ends of the cylinder in communication, this communication being regulated by a faucet or cock, I). When the faucet is closed the piston isarrested and held prac-= tically immovable. When it is opened the fluid is again free to pass through the tube from one end of the cylinder to the other, and the piston is consequently free to move back and forth.

Instead of coupling the piston-rod 0 directly to the wheel, as in the former case, I now couple the pis-- ton-rod to a crank-shaft, (Z, by the connecting-rod c.

The crank-shaft is arranged at a suitable distance from the axle j of the car, so that 'a loose gear, g, which it carries may engage with a gear, 71, fixed upon the axle.

The gear g, which, as I have said, is loose upon the crank-shaft, is united with a circular ratchet, i, which engages with spring pawls k, mounted upon a disk, I, fixed to the crank-shaft.

The arrangement of these parts is such that when the car is moving in the direction indicated by the arrow, that is, ascending'the grade, the gear 9 and ratchet i will revolve without communicating motion to the crank-shaft, the pawls It riding over the ratchetteet-h.

\Vhen, on. the contrary, the car descends, the ratchet and pawls are thrown into mesh, and the piston-rod is thus thrown into direct communication with the wheels of they car, and if the faucets or cocks b are closed, the motion of the wheels will be at once arrested. 7

Upon the axle is mounted the pinion m, which engages with the central rack n on the track, in the usual manner.

Instead of the specific devices herein described, it

is obvious that other devices, such as clutches, etc., may be employed for the purpose of allowing the piston-rods to remain at rest during the upward travel of the car, at the same time maintaining them so that they shall be instantaneously thrown into communication with the wheels in case the motion of the car should be reversed.

Having now described my invention and the mam nor in which the same is or may be carried into effect,

What I claim and desire to secure by Letters Patent is- The combination of the piston-rods of the air-tight cylinders and the car-axle or wheels, with the means herein described, or their mechanical equivalent, for coupling or connecting the same, under the arrangement specified, so that the pistons while remaining at rest during the upward travel of the car, shall be at once thrown into operation when the car begins to descend, substantially as and for the purposes set forth.

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

\Vitnesscs: SYLVESTER MARSH.

Evan'rs W. FARR, J onn FARR. 

